Patent GB-534699-A (GB)
Title: Polymeric compounds suitable for filaments, films, coating compositions, plastics and the like
IPC: C08L75/02
Filed: 1939-09-13
Abstract: 534,699. Polyamides. DU PONT DE NEMOURS & CO., E. I. Sept. 13, 1939, No. 25701. Convention date, Sept., 15, 1938. [Class 2 (iii)] Polythioureas are formed by condensing polyamines, preferably diamines, with a thiourea-forming derivative of thiocarbonic acid until the product has an intrinsic viscosity of at least À12. The polyamines used have at least two amino groups containing hydrogen separated by at least four carbon atoms in an open chain, at least three carbon atoms in a monocylic body or at least four in a dicyclic body. Suitable condensation processes include (A) the heating of a polyamine with an ester of trithiocarbonic acid (B) the heating of carbon bisulphide with a polyamide (C) the heating of a bis (dithiocarbamate) with a diamine (D) the heating of ammonium thiocyanate of a diamine (E) The heating of a polyisothiocyanate with a polyamine. Other thiourea-forming derivatives of thiocarbonic acid that may be reacted with the polyamine include sulphanhydrates, thioamidos, acid halides, half esters, diesters (with alcohols or phenols). Specified polyamines that may be used include decamethylene,. diamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, di- (hexamethylene)-triamine, tetramethylenediamine, pentamethylenediamine, m-phenylenediamine, p - phenylenediamine, benzidine, m-toluylenediamines, 2:5-dimethyl-1:6-diaminohexane, 1:4-diaminocyclohexane, 1:10-bis (methylamino) decane, triglycoldiamine, thioglycoldiamine. Mixtures of polyamines and thiourea-forming derivatives may be used. The reaction, which may take place in the presence of a diluent such as a phenol, is preferably effected in the absence of oxygen by operating in vacuum, in the presence of an inert gas such as nitrogen, argon, helium or hydrogen or in the presence of antioxidants such as syringic acid. Excess of one reactant or small amounts of monoamines or monocarboxylic acids may be used in the reaction. The reaction vessels used may be constructed of, or lined with, glass, porcelain, enamel, silver, gold, tantalum, platinum, palladium, rhodium, alloys of platinum with palladium or rhodium and chromium-nickel steels. Catalysts such as sulphur may be used. The polythioureas may be converted in filaments by melt, wet or dry spinning and the filaments are preferably cold drawn ; they may be de-lustred, preferably by the addition of a finely divided material of different refractive index such as titanium dioxide, zinc oxide, zinc sulphide, barium sulphate, carbon black, copper phthalocyanine pigments or non-phenolic polymer clear compounds. The filaments, which may be set by steaming, may be worked up into woven or knitted fabrics and mixed fabrics with other fibres. The products may also be used in the manufacture of films, foils, sheets, ribbons, bands, rods, hollow tubes, interlayed for safety, glass and bristles. Addition of the polythiourea to a polyamide improves the properties of products therefrom. In examples: (1) decamethylenediamine or hexamethylenediamine is reacted with ethyl methyl trithiocarbonate to yield a polythiourea which may be converted into fibres direct from the melt or which may be cast into sheets by hot-pressing between plates covered with aluminium foil, the finished sheet being cold-rolled or directly sandwiched between two plates of glass and hot-pressed to yield a safety glass; (2) m-phenylenediamine is reacted with ethyl methyl trithiocarbonate in the presence or absence of phenol ; (3) decamethylenediamine is allowed to stand with ethyl methyl trithiocarbonate in the cold, dissolved in phenol and then heated ; (4) m-phenylenediamine is heated with ethyl methyl trithiocarbonate in the presence of phenol; (5) solutions of carbon disulphide and hexamethylenediamine in methanol are mixed and the precipitate obtained, after drying, is heated in the presence of phenol and of sulphur (as a catalyst)À,' (6) decamethylenediamine is reacted with dimethylhexamethylenebisdithiocarbonate in the presence of phenol ; (7) decamethylenediamine is.reacted with ammonium thiocyanate; (8) decamethylenediamine is reacted with decamethylene diisocyanate in the presence of cresol. In each example. the polymers may be. converted into filaments. Ethyl methyl trithiocarbonate is prepared by treating ethyl mercaptan with carbon di-. sulphide in the presence of aqueous potassium hydroxide and treating the. product with dimethyl sulphate. Alkyl mercaptans are prepared in the forma-. tion of the polythioureas by re-acting dialkyl trithiocarbonates with polyamines or by reacting bis(dithiocarbamates) with polyamines. Dimethylhexamethylene bis (dithiocarbamate) is prepared by treating hexamethylenediamine with carbon disulphide in the presence of aqueous potassium hydroxide and reacting the products with dimethyl sulphate.